MgH分子低激发态的光谱和分子常数

利用Davidson修正的内收缩多参考组态相互作用(MRCI+Q)方法,结合相关一致全电子基aug-cc-pw CV5Z优化计算了MgH分子5个低激发电子态(5Λ–S)的势能曲线.为了得到高精确的光谱性质,计算中引入核价电子相关和相对论效应修正.利用LEVEL8.0程序拟合修正的Λ-S束缚态的势能曲线,得到了相应的光谱常数、振动能级和分子常数,结果与近来的理论计算相比,本文的数值更接近实验值.这些结果说明高精度的计算方法和引入相关修正对分析光谱性质是非常必要的,为进一步研究MgH分子高激发态的光谱和跃迁特性提供可靠的实验和理论参考.     

MgH分子低激发态的光谱和分子常数

利用Davidson修正的内收缩多参考组态相互作用(MRCI+Q)方法,结合相关一致全电子基aug-cc-pwCV5Z优化计算了MgH分子5个低激发电子态(5Λ–S)的势能曲线. 为了得到高精确的光谱性质,计算中引入核价电子相关和相对论效应修正. 利用LEVEL8.0程序拟合修正的Λ-S束缚态的势能曲线,得到了相应的光谱常数、振动能级和分子常数,结果与近来的理论计算相比,本文的数值更接近实验值. 这些结果说明高精度的计算方法和引入相关修正对分析光谱性质是非常必要的,为进一步研究MgH分子高激发态的光谱和跃迁特性提供可靠的实验和理论参考.     

单氯化锶分子低激发态的光谱及跃迁特性

利用Davidson修正的内收缩多参考组态相互作用(ic-MRCI+Q)方法,结合相对论有效芯赝势基(augcc-pV5Z-PP)作为Sr原子和相关一致五重基aug-cc-pV5Z为Cl原子的计算基组,优化计算了单氯化锶(Sr~(35)Cl)分子14个低激发电子态的势能曲线和跃迁偶极矩.为了获得更加精确的光谱参数,计算中同时引入核价电子相关和相对论效应修正势能曲线.利用LEVEL 8.0程序拟合修正的势能曲线,得到相应电子态的光谱常数、振动能级和分子常数等光谱性质,结果与近来的已获得的理论计算和实验值符合得较好,同时给出了Franck-Condon因子和辐射寿命等跃迁性质.这些精确的光谱跃迁特性可为进一步构建Sr~(35)Cl分子激光冷却方案提供理论支持.     

多参考组态相互作用方法研究MgCl分子低激发态的光谱和分子常数

利用Davidson修正的内收缩多参考组态相互作用(ic-MRCI+Q)方法,结合相关一致全电子基aug-cc-pwCV5Z优化计算了MgCl分子5个低激发束缚电子态(5Λ–S)的势能曲线.为了得到高精度的光谱参量,计算中引入核价电子相关和相对论效应修正.基于修正的Λ-S束缚态的势能曲线,利用LEVEL8.0程序拟合得到相应的光谱常数、振动能级和分子常数,结果与其它的理论计算相比,本文的数值更接近实验值.这些结果说明高精度的计算方法和引入相关修正对分析光谱性质是非常必要的,这为进一步研究MgCl分子高激发态的光谱和跃迁特性提供理论支持.     

MRCI+Q理论研究SiSe分子X1Σ+和A1Π电子态的光谱常数和分子常数

采用Davidson修正的内收缩多参考组态相互作用方法(MRCI+Q)及相关一致基aug-cc-pV5Z和aug-cc-pVQZ分别计算了SiSe分子X¹Σ⁺和A¹Π电子态的势能曲线. 为提高势能曲线的计算精度, 利用两点总能量外推公式, 将两个电子态的势能曲线外推至完全基组极限, 并对其进行了标量相对论修正, 相对论效应是在cc-pV5Z基组水平下使用三级Douglas-Kroll-Hess哈密顿算符计算的. 利用MRCI+Q/Q5+DK理论水平的势能曲线获得了这两个态的光谱常数(T_e, D_e, R_e, ω_e, ω_ex_e, ω_ey_e, B_e和α_e)和J=0时前30个振动态的B_υ和D_υ等分子常数. 其值与已有的实验结果非常一致. 本文得到的光谱常数和分子常数达到了很高精度, 能为进一步的光谱实验和理论研究提供可靠参考. 关键词： 势能曲线 基组外推和标量相对论修正 光谱常数 分子常数     

理论研究BeS(X~1∑~+)的光谱常数及分子常数

采用Davidson校正的内收缩多参考组态相互作用方法（MRCI+Q）结合相关一致五重基cc-pV5Z在二阶Douglas-Kroll Hamiltonian近似下,计算了BeS分子X¹∑⁺态的势能曲线.对势能曲线进行核价相关效应修正计算,得到了同时含有核价相关效应修正及相对论效应的势能曲线.拟合修正的势能曲线,获得BeS（X¹∑⁺）的光谱常数R_e,ω_e,ω_ex_e,ω_ey_e,B_e,α_e,β和D₀,分别为:0.17429 nm,997.06cm^-1,6.1056 cm^-1,0.0041 cm^-1,0.7893 cm^-1,0.006657 cm^-1,6.8002×10^-9cm^-1和4.2609 eV.与已有的实验结果及其它理论结果的比较表明,本文BeS（X¹∑⁺）的光谱常数的计算结果达到了较高的精度.通过求解双原子分子核运动的径向Schr（o|¨）nger方程,找到了非转动BeS（X¹∑⁺）的前40个振动态.针对每一振动态还分别计算了相应的振动能级、惯性转动常数和离心畸变常数等分子常数.     

MRCI方法研究CSe(X1Σ+)自由基的光谱常数和分子常数

采用内收缩多参考组态相互作用方法在0.08—2.5 nm的核间距范围内计算了CSe(X¹Σ⁺)自由基的势能曲线.为确保势能曲线的计算精度,C原子使用较大的相关一致基aug-cc-pV5Z,Se原子使用最大的相对论赝势基aug-cc-pV5Z-pp.对CSe(X¹Σ⁺)自由基的势能曲线进行了拟合,并进行了同位素识别,得到了该自由基6个主要同位素分子(¹²C^{74< 关键词： 同位素识别 势能曲线 光谱常数 分子常数}     

BeF~+离子电子态的光谱常数研究

采用从头计算方法(Ab)研究BeF~+离子的光谱性质.在icMRCI+Q/Q5+CV+DK的理论水平下计算得到了BeF~+离子的16个态的势能曲线,为了提高精确度,对势能曲线进行核价相关修正及相对论修正两种修正计算,画出了16个态的势能曲线图.拟合势能曲线得到其光谱常数(D_e,T_e,R_e,ω_e,ω_ex_e,ω_ey_e,B_e,α_e和β_e).分别计算了各个振动态对应的的振动能级.     

BCl分子X~1Σ~+,a~3Π和A~1Π态的光谱性质

采用Davidson修正的内收缩多参考组态相互作用方法(MRCI+Q)及Dunning等的相关一致基aug-ccpV6Z计算了BCl分子X1Σ+,a3Π和A1Π态的势能曲线.利用总能量外推公式,将这3个态的总能量分别外推至完全基组极限.对势能曲线进行核价相关修正及相对论修正计算,得到了同时考虑这两种修正的外推势能曲线.拟合势能曲线得到了3个态的主要光谱常数Te,Re,ωe,ωexe,Be,αe和De等,它们与已有的实验结果较为一致.利用获得的势能曲线,通过求解双原子分子核运动的径向Schrdinger方程,找到了BCl分子X1Σ+,a3Π和A1Π态的全部振动态,并得到了相应的振动能级和惯性转动常数等分子常数.还计算了a3Π—X1Σ+和A1Π—X1Σ+的跃迁偶极矩、Franck-Condon因子,预测了若干跃迁的辐射寿命.     

MRCI方法计算CP和CP-低能电子态的光谱常数

采用内收缩多参考组态相互作用（MRCI）方法结合相关一致基aug-cc-pV5Z计算了CP分子X2Σ+,A2Π和B2Σ+和CP-离子X1Σ+电子态的势能曲线．考虑了Davidson、相对论和核价相关修正对势能曲线的影响．本文的相对论修正是利用二阶Douglas-Kroll 哈密顿近似在cc-pV5Z基组水平进行的;同时核价相关修正也是在cc-pV5Z基组水平进行的．为了提高计算精度,将能量外推至完全基组极限处,得到外推的势能曲线．对这些势能曲线进行拟合,得到各种水平下四个电子态的光谱常数(Te,Re,ωe,ωexe,αe和Be),并详细分析了Davidson修正、相对论修正和核价相关修正及基组外推对光谱常数的影响．与其它理论结果和实验数据进行比较,可知本文的结果更精确、更完整．     

Accurate spectroscopic constants of the lowest two electronic states in S_2 molecule with explicitly correlated method

A computational scheme for accurate spectroscopic constants was presented in this work and applied to the lowest two electronic states of sulfur dimer. A high-level ab initio calculation utilizing explicitly correlated multireference configuration interaction method(MRCI-F12) was performed to compute the potential energy curves(PECs) of the ground triplet X3-Σgand first excited singlet a1?g states of sulfur dimer with cc-p CVX Z-F12(X = T, Q) basis sets. The effects of Davidson modification, core–valence correlation correction, and scalar relativistic correction on the spectroscopic constants were examined. The vibration–rotation spectra of the two electronic states were provided. Our computational results show excellent agreement with existing available experimental values, and the errors of main spectroscopic constants are within 0.1% order of magnitude. The present computational scheme is cheap and accurate, which is expected for extensive investigations on the potential energy curves or surfaces of other molecular systems.     

Configuration interaction study on low-lying states of AlCl molecule

High-level ab initio calculations of the Λ–S states for aluminum monoiodide(Al Cl) molecule are performed by utilizing the explicitly correlated multireference configuration interaction(MRCI-F12) method. The Davidson correction and scalar relativistic correction are investigated in the calculations. Based on the calculation by the MRCI-F12 method, the spin–orbit coupling(SOC) effect is investigated with the state-interacting technique. The adiabatic potential energy curves(PECs) of the 13 Λ–S states and 24 Ω states are calculated. The spectroscopic constants of bound states are determined,which are in accordance with the results of the available experimental and theoretical studies. Finally, the transition properties of 0~+(2)–X0~+, 1(1)–X0~+, and 1(2)–X0~+ transitions are predicted, including the transition dipole moments(TDMs),Franck–Condon factors(FCFs), and the spontaneous radiative lifetimes.     

BF自由基X~1Σ~+和a~3Π态光谱常数和分子常数研究

采用内收缩多参考组态相互作用方法和相关一致基aug-cc-pV6Z,对BF自由基X~1∑~+和a~3Π态的势能曲线进行了研究.计算是在0.095-133 nm的核间距内进行的.为获得更准确的结果,计算中还考虑了Davidson修正、相对论修正及核价相关修正对势能曲线的影响.相对论修正采用的方法是二阶DouglasKroll哈密顿近似,修正计算是在cc-pV5Z基组水平上进行的.核价相关修正使用的是cc-pCV5Z基组.利用得到的势能曲线,拟合出了各种修正下BF自由基X~1∑~+和a~3Ⅱ态的光谱常数De,Re,ωe,ωeχe,ωeye,Be和αe、并与实验结果进行了比较.结果表明:考虑Davidson修正、相对论修正和核价相关修正后得到的光谱常数最接近实验结果.利用修正后的势能曲线,通过求解径向振转Schr6dinger方程,找到了转动量子数J=0时这两个电子态的全部振动态,并计算了每一电子态前20个振动态的振动能级、惯性转动常数和离心畸变常数,其值与已有的实验结果较为一致.本文得到的光谱常数和分子常数达到了很高的精度,能为进一步的光谱实验提供可靠的参考.     

BF自由基X1∑+和a3∏态光谱常数和分子常数研究

采用内收缩多参考组态相互作用方法和相关一致基aug-cc-pV6Z, 对BF自由基X¹∑⁺和a³∏ 态的势能曲线进行了研究. 计算是在0.095---1.33 nm的核间距内进行的. 为获得更准确的结果, 计算中还考虑了Davidson修正、相对论修正及核价相关修正对势能曲线的影响. 相对论修正采用的方法是二阶DouglasKroll哈密顿近似, 修正计算是在cc-pV5Z基组水平上进行的. 核价相关修正使用的是cc-pCV5Z基组. 利用得到的势能曲线, 拟合出了各种修正下BF自由基X¹∑⁺和a³∏ 态的光谱常数D_e, R_e, ω_e, ω_ex_e, ω_ey_e, B_e和α_e、并与实验结果进行了比较. 结果表明: 考虑Davidson修正、相对论修正和核价相关修正后得到的光谱常数最接近实验结果. 利用修正后的势能曲线, 通过求解径向振转Schrödinger方程, 找到了转动量子数J = 0时这两个电子态的全部振动态, 并计算了每一电子态前20个振动态的振动能级、惯性转动常数和离心畸变常数, 其值与已有的实验结果较为一致. 本文得到的光谱常数和分子常数达到了很高的精度, 能为进一步的光谱实验提供可靠的参考.     

Excited-states and spectroscopic properties of superoxide anion: a theoretical study including spin–orbit coupling

ABSTRACT

The potential energy curves (PECs) of 24 Λ–S electronic states of superoxide anion (O₂^?), which correlated with the first dissociation channel, were calculated using a high-accuracy internally contracted multireference configuration interaction (icMRCI) methodology with the Davidson correction in conjunction with the correlation-consistent basis sets. The core electron correlation and scalar relativistic corrections as well as basis set extrapolation were included. The spin–orbit coupling was also taken into account by using the state interaction approach with the Breit–Pauli Hamiltonian. The PECs of 54 Ω states generated from the 24 Λ–S states were constructed and described in detail. The spectroscopic constants of the seventeen Λ–S and 37 Ω bound states were evaluated and the vibrational properties of some weakly bound states were predicted. Comparing with the available experimental and theoretical data shows that the computational strategy employed is suitable and highly accurate for this system.     

icMRCI方法研究NS~±离子体系基态光谱

本文采用高精度的内收缩多参考组态相互作用方法(icMRCI)计算了NS~±体系基态的势能曲线,为了能够获得精确结果在计算过程中考虑了能量的Davidson修正.之后基于获得的势能曲线求解核的一维Schr?dinger方程,得到了NS~±离子体系基态的光谱数据R_e、ω_e、ω_eχ_e、B_e、α_e.发现本文理论计算结果与已有的实验数据和现有理论值吻合得很好.并进一步计算了NS~+(X~1Σ~+)基态和NS~-(X~3Σ~-)基态的振动能级G(ν)和体系转动量子数J=0时的分子离心畸变常数B_ν、D_ν.与实验数据和其他理论结果的比较表明本文计算结果达到了较高精度能够为这一离子体系的进一步研究提供参考依据.     

MRCI+Q study of the low-lying electronic states of CdF including spin-orbit coupling

Cd F molecule, which plays an important role in a great variety of research fields, has long been subject to numerous researchers. Due to the unstable nature and heavy atom Cd containing in the Cd F molecule, electronic states of the molecule have not been well studied. In this paper, high accurate ab initio calculations on the Cd F molecule have been performed at the multi-reference configuration interaction level including Davidson correction(MRCI + Q). Adiabatic potential energy curves(PECs) of the 14 low-lying Λ–S states correlating with the two lowest dissociation limits Cd(~1S_g) + F(~2P_u) and Cd(~3P_u) + F(~2P_u) have been constructed. For the bound Λ–S and ? states, the dominant electronic configurations and spectroscopic constants are obtained,and the calculated spectroscopic constants of bound states are consistent with previous experimental results. The dipole moments(DMs) of 2 Σ+ and 2Π are determined, and the spin–orbit(SO) matrix elements between each pair of X2Σ+, 22Σ+, 12Π, and 22Π are obtained. The results indicate that the sudden changes of DMs and SO matrix elements arise from the variation of the electronic configurations around the avoided crossing region. Moreover,the Franck–Condon factors(FCFs), the transition dipole moments(TDMs), and radiative lifetimes of low-lying states-the ground state X2Σ+are determined. Finally, the transitional properties of 22Π–X2Σ+and 22Σ+–X2Σ+are studied. Based on our computed spectroscopic information of Cd F, the feasibility and challenge for laser cooling of Cd F molecule are discussed.     

CN~+离子电子结构和跃迁性质的理论研究

采用多组态参考相互作用方法和AV5Z-DK基组对CN~+离子的两个解离极限C~+(~2P_u)+N(~2D_u)和C~+(~2P_u)+N(~4S_u)下的X~1Σ~+、a~3Π、~1Δ和A~1四个电子态的势能曲线、永久偶极矩和振动能级进行了计算.为保证计算结果的精确性,在计算中考虑了Davidson修正.基于求得的势能曲线,数值求解一维径向薛定谔方程得到了各个电子态的光谱数据,并与实验值和已有的理论值吻合较好.除此之外,对A~1Π→X~1Σ~+和1~1Δ?A1~Π的跃迁性质进行了研究,同时通过跃迁的弗兰克-康登因子及辐射寿命,对CN~+离子激光冷却的可行性进行了分析.     

MCHF+BP Approaches of Hyperfine Interaction Constants in 45SII

Multi-configuration Hartree-Fock and configuration interaction calculations of hyperfine structure constants for 3d^{2 3}P states of ScII are reported. It is very important to consider core polarization (especially spin polarization) and core-core correlation as well as valence correlation for accurate calculation of hyperfine constants. The relativistic correction (through Breit-Pauli approximation) as well as finite-nuclear-mass and fnite-nuclear-size-corrected values of the hyperfine constants for ScII are in good agreement with the most accurate experimental values and better than other ab initio theoretical results.